Mississippian rocks are exposed in the Llano region and in the Hueco
Mountains of the Trans-Pecos area. The Trans-Pecos rocks primarily
contain brachiopods with some bryozoans and gastropods.
The central Texas Mississippian rocks are much more fossiliferous and
some of the material is well preserved. Fossils reported from this area
include brachiopods (Pl. 17), crinoids, gastropods, cephalopods,
trilobites, and ostracodes.